Alarms



R. W. CABELL May 7, 1957 ALARMS Filed Jan. 19, 1955 y M m W M 0 m z 1TQ1 Q) M, v w M u w E INVENTOR. BY 61 w new United States Patent ALARMSRoger W. Cabell, Providence, R. I., assignor to Loretta E. Cabell andLaura W. Cabell, both of Providence,

Application January 19, 1955, Serial No. 482,709 1 Claim. (Cl. 200142)This invention relates to alarm systems for use in houses or otherstructure using electrical power, and is illustrated herein as embodiedin a fire alarm system although it will be understood that the inventionis also applicable to burglar alarm systems and the like.

Many types of fire alarm systems suitable for instal lation in existingdwellings have been proposed. One type comprises a self-contained unitwhich may be placed in a suitable location in the building and consistsof a thermally responsive element arranged to close a circuit to a bellor other form of signal when the temperature at the unit reaches apredetermined value. The bell may either be energized from a battery orwired into the house circuit. In the first case, the battery must beperiodically replaced or the alarm is not reliable. In the other case,the necessary wiring involves more expense than the average homeowner iswilling to assume, particularly in the event that maximum protection isdesired by locating the alarm at strategic locations throughout thebuilding to be protected which may be remote from the location to beprotected.

Another system utilizes a spring actuated bell which is automaticallyoperated when the temperature at the device reaches a predeterminedvalue. The length of time that the alarm will sound is necessarilylimited and the spring may become unwound or break without the ownerrealizing it, thus adversely affecting the reliability of the device.With such systems, the alarms are not readily located remote from thethermally responsive element without extensive wiring which further addsto the expense.

Despite the appalling losses of life and property every year due tofires, and the desirability of providing a reliable fire alarm system inhomes, apartments, etc., relatively few such systems have beeninstalled, and the average homeowner is without any fire alarmprotection even though aggressive efforts to mechandise such systems andothers have been made. The present invention has for its object theprovision of an inexpensive but reliable alarm system which utilizes anyexisting electric light or power circuits in any electrically wiredstructure and can readily be installed therein at low cost.

To this end and in accordance with a feature of the invention,thermo-responsive switch elements are plugged into or connected to lightsockets or appliance outlets at strategic locations within thestructure, each element being arranged to cause a short in the circuitinto which the element is connected whenever the temperature at theelement reaches a predetermined value, causing the opening of a circuitinterrupter which actuates an alarm powdered by the circuit betwen theinterrupter and the source of supply to warn persons within or outsidethe structure of the impending danger.

In accordance with a further feature of the invention, the systeminvolves a novel circuit interrupter which, in response to an overloadin the circuit, closes an auxiliary circuit in which the alarm isincorporated.

The above and other features of the invention, including novel detailsof construction and combinations of elements, will now be described withreference to the drawing and pointed out in the claim.

In the drawings,

Fig. 1 is a diagrammatic view of one form of system in which theinvention is embodied;

Fig. 2 is a section through one of the elements of the system, and

Fig. 3 is a section through another element of the system.

Referring to Fig. 1, the wires L1, L2 represent the usual power linesentering a building and passing to the usual fuse box 10. A circuitcomprising wires 12, 14 is illustrated as servicing one portion of thebuilding, such as the lower floor or basement, and another circuit 16,18 services another portion of the building. Circuit interrupters orfuses 20 control the current through the wires 14, 18 for providingoverload protection for-the two circuits.

Each of the circuit interrupters is illustrated as comprising a base 22formed of suitable electric insulating material and having a pair ofcontactor members 24, 26 as in the conventional screw type fuse. Thecontact members are electrically connected by a strip or wire 28 offusible metal which melts upon the passage of a current of predeterminedamperage therethrough to interrupt the current flow, and by a flexibleconnection 30.

The fuse also includes means for closing another circuit when anoverload in the controlled circuit causes the wire 28 to melt. For thispurpose, to the inner end of the wire 28 is connected a rod 32 ofelectrical insulating material guided for movement axially of the base22 by an apertured plate 34 clamped between the base 22'and a head 36secured to the base by a clamping ring 38. The outer end of the rod 32carries a switch or conductor member 40 urged toward a pair of contactmembers 42 by a spring 44. Normally however the wire 28 holds theconductor member in the position illustrated against the action of thespring, but upon an overload in the controlled circuit suificient tocause melting of the wire 28, the spring 44 forces the conductor member40 into engagement with the contact members 42 to establish a circuitthrough them.

Across each of the circuits 12, 1.4, and 16, 18 are illustrated lightbulb sockets and/or appliance outlets 45 into which may be connected anysuitable electric appliance. Connected into certain of the bulb socketsor appliance outlets are temperature responsive fuse blowers 46 whichare arranged to cause a short in the circuit when the temperature in thevicinity of the fuse blower attains a predetermined value. One formwhich this fuse blower may assume is illustrated in Fig. 3 and is shownto comprise a base 48 of electrical insulating material carrying contactmembers 50, 52 adapted to be received in a conventional bulb socket.Connected to the members 5%, 52 are con ductors 54 having terminalportions 56 which lie adja cent to a conical internal portion of thebase 43.

Normally adjacent to but held out of contact with the terminal portions56 is a conical conductor 58 carried by a rod 60 guided in a plate 62clamped between the base 48 and a head 64 secured in the base by aclamping ring 66. The conductor is held out of contact with the tcrminalportions 56 of the conductors 54 against the action of a spring 68 by awire or link 70 of fusible metal secured between the rod 50 and the head64. The head 64 may be apertured or be formed of an open ribbedconstruction so that the wire 70 is affected directly by the temperatureof the ambient atmosphere, which will cause melting of the wire when thetemperature reaches a predetermined value, thus permitting movement ofthe conductor 58 into engagement with the terminal portions 56, causinga direct short across the circuit in which the member 46 is con-Patented May 7, 1957 nected. A screen 72 covers the openings in the head64 to protect the wire 70 without insulating it from the atmosphere.

I It will be understood that the fuse blowers 46 may either be of thescrew-in type as shown, or may be provided with a pair of prong contactmembers for plugging into the conventional appliance outlet, or may beinserted into extension cords so that they may be located in any desirable spot in a room. Any desired number of fuse blowers may be insertedin a circuit to provide maximum protec tion for the building.

Connected to the lines L1, L2 on the input side of the fuse box is astep down transformer 74 to one side of the secondary of which areconnected bells 76, 78 each of which is connected through contactmembers 42, 42 of the circuit breakers 20. Thus, upon the existence of ashort in either of the circuits caused by any of the fuse blowers byreason of a fire in its vicinity, the wire 28 in the circuit breakercontrolling the particular circuit will melt, and the contact member 42will be connected to complete a circuit through the associated bell 76to warn an occupant or attendant of the building. Any other form ofsignal either visible or audible, may of course be substituted for thebells illustrated, and because of their low voltage actuation, they maybe located at any desired place within the building and connected intothe system with a minimum of difliculty.

Additional alarms 88 may be located outside of the building in parallelwith the interior alarms and controlled by switches 82 so that if thebuilding is to be left unoccupied and the switches are closed, theoutside alarms will operate should a fire start within the building.

In addition to the usefulness of my system in providing fire protectionto private dwellings, it is particularly useful in apartment buildingsand the like, in which the circuits to the several apartments arecontrolled by a central fuse box. Such buildings often have an attendantor watchman in constant service, in which case all the alarms might belocated in the vicinity of the fuse box, and the fuse blowers locatedwherever desired throughout the structure, thus providing adequateprotection at small cost without having to string wires throughout thebuilding. The same of course applies where a group of buildings, many ofwhich are frequently left unattended, such as buildings on a farm, haveelectrical service controlled by a fuse box in the main building orhouse.

It will be understood that in place of the fuse blowers 46, which closethe circuit in response to the attainment of a predetermined hightemperature of the air surrounding them, a control which operates inresponse to an abnormally rapid rise in temperature may be substituted.Thus, the alarm may be operated either in response to the attainment ofa predetermined temperature or in response to a rapid rise intemperature, either of which will reflect the presence of a fire in thevicinity of the control member.

It will be apparent that my system may also be employed as a burglaralarm system. In such case, all that is required is to replace orsupplement the fuse blowers 46 by switch members which will close andshort the circuits into which they are connected upon intrusion ofunwanted persons within the building. Such devices might be operated byopening of windows, walking on carpets etc., and disconnected from thecircuit when burglar protection is not needed or desired.

it is to be understood that my present invention is capable ofexemplification in other and further modifications not shown ordescribed in this application for Letters Patent, but all modificationsinsofar as they embody the principle of the present invention are to bedeemed within the scope and purview of the appended claim.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

A circuit breaker comprising a body member formed of two parts, apartition between said parts forming two chambers, a pair of electricalcontact members in an end wall of one chamber, a rod slidable throughsaid partition toward said contact members, conducting means carried byan end of said rod arranged, when the rod is moved toward said end wall,to close a circuit through said contact members, a spring urging saidrod toward said end wall, a pair of conductor members carried by the endwall of the other chamber of said body member, a fusible elementconnecting said other conductor members, said fusible element beingconnected to said rod and holding it away from the first-mentioned endwall against the action of said spring whereby, upon an overload in thecircuit through the fusible element, the element will rupture,interrupting the circuit through said conductor members and permittingmovement of the red by the spring and closure of the circuit through thecontact members.

References Cited in the file of this patent UNITED STATES PATENTS1,068,440 McCarthy iuly 29, 1913 1,734,071 Blalack Nov. 5, 19291,813,844 Gilbert July 7, 1931 3 1,927,744 Jones Sept. 19, 19332,011,112 McBrien et a1 Aug. 13, 1935 2,085,386 Phillips et a1 July 29,1937

